LTCast LTCast
/ A/B Loop
Manual A/B Loop

A/B Loop

A/B Loop lets you mark two points in the timeline and repeat the section between them continuously. All protocol outputs loop in sync with the audio — no separate configuration is needed on receiving devices.

Setting loop points

  • Set Loop A (start) — press [ or click the A button in the transport while the playhead is at the desired start position
  • Set Loop B (end) — press ] or click the B button while the playhead is at the desired end position

You can set A and B while the transport is playing or stopped. Setting A while playing marks the current playback position. Setting B while playing marks the position at the moment you press the key.

Loop A and B do not need to be set in order — you can set B before A if that is easier during a fast rehearsal pass.

Active looping

Once both A and B are set, the transport loops. Behavior during looping:

  • Playback reaches the B point and immediately jumps back to the A point without stopping
  • LTC audio resets to the A timecode address on each loop cycle
  • MTC sends a Full Frame locate message at the loop-back point
  • Art-Net and OSC update to the A position on each loop
  • The loop region is shown as a highlighted band on the waveform

Clearing the loop

  • Press [ while the loop is active — this clears both the A and B points and disables looping
  • Click Clear Loop in the transport controls
  • Clicking the A button again while looping is active also clears the loop

After clearing, playback continues from the current position without looping.

Saving loop points

Loop A and B positions are saved with the project file. When you reopen a .ltcast file, the loop markers are restored to their saved positions. This makes it easy to set up rehearsal loops during preparation and recall them at the venue.

Loop vs Setlist auto-advance

A/B Loop is designed for rehearsal: repeating a section to practice cues or check sync. During a live show, use Setlist auto-advance to move through songs sequentially. Running the A/B loop during a show will cause the transport to cycle and never advance to the next song automatically.